Cycle 1 (2011 Deadline)
Assessment of the tropospheric HONO budget: instrumental development and field measurments
PI: Charbel Afif, Université Saint Joseph de Beyrouth
US Partner: Sebastian Dusanter, University of Indiana
Project Dates: May 2012 - October 2013
Climate change is one of the most important environmental concerns of the 21st century, and there are concerns regarding atmospheric warming due to increases of greenhouse gas emissions. Reliable climate projections will depend on how well models of atmospheric chemistry can forecast concentrations of greenhouse gases, whose lifetimes depend on the global concentration of the hydroxyl (OH) radical. However, there are still large uncertainties related to the atmospheric OH budget. Recent studies focusing on the chemistry of nitrous acid (HONO), an important source of the OH radical, indicate that model-predicted concentrations of HONO do not agree with field measurements performed in various environments (urban, rural, forests, etc.). These results suggest that our understanding of HONO chemistry is incomplete and call into question our ability to model the atmospheric oxidative capacity and therefore our ability to predict future changes in the atmosphere.
The project will support construction of a reliable instrument (NitroMAC) at the Université Saint Joseph de Beyrouth to measure atmospheric HONO concentrations. The principal investigator will work to develop a calibration source of HONO and compare data collected by his new NitroMAC instrument with those gathered by his US partner’s HONO instrument. NitroMAC will be deployed by the collaborating researchers during intensive field campaigns in both the United States and Lebanon, with the US partner to provide the infrastructure for field measurements and part of the equipment necessary for the intercomparison experiment. Collaborations through the field campaign measurements and subsequent data interpretation will promote the sharing of knowledge between the researchers involved. The research outcomes of the project should also benefit the atmospheric science community by adding more constraints to the HONO budget and by improving understanding of the oxidative capacity of the atmosphere. Furthermore, the project will initiate air quality studies in Lebanon and will help promote the development of efficient strategies for pollution control.
Summary of Recent Activities
In February 2013, Dr. Afif and his postdoctoral fellow Dr. Joelle Bechara spent a week visiting their U.S. partner Dr. Dusanter and his colleagues at Indiana University. The visit featured a presentation on research activities by the U.S. group, a comparative presentation on measurement techniques, discussions on calibration techniques and on future logistical aspects of the upcoming field campaign, and meetings with various faculty members at IU in order to discuss their different research fields. At the request of U.S. co-partner Dr. Philip Stevens, Dr. Afif presented a seminar about his PEER Science project for IU faculty members. The last remaining components of the new NitroMAC instrument and its calibration source NitroCal are expected to arrive at USJ in April, after which the devices will be fully assembled and prepared for field testing and initial data collection in June 2013. In the meantime, Dr. Afif and Dr. Bechara will be organizing a conference on the project in May 2013. The two researchers will also return to Indiana in July to participate in a field campaign organized by their U.S. partners. During the campaign, they will test the reliability of HONO measurements made with their NitroMAC instrument and compare the results with those from a different type of instrument developed by the U.S. partners.
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